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John Johansen12557dc2017-01-16 00:42:13 -08001/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor lib definitions
5 *
6 * 2017 Canonical Ltd.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation, version 2 of the
11 * License.
12 */
13
14#ifndef __AA_LIB_H
15#define __AA_LIB_H
16
17#include <linux/slab.h>
18#include <linux/fs.h>
19
20#include "match.h"
21
John Johansen57e36bb2017-01-16 00:42:26 -080022/* Provide our own test for whether a write lock is held for asserts
23 * this is because on none SMP systems write_can_lock will always
24 * resolve to true, which is what you want for code making decisions
25 * based on it, but wrong for asserts checking that the lock is held
26 */
27#ifdef CONFIG_SMP
28#define write_is_locked(X) !write_can_lock(X)
29#else
30#define write_is_locked(X) (1)
31#endif /* CONFIG_SMP */
32
John Johansen12557dc2017-01-16 00:42:13 -080033/*
34 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
35 * which is not related to profile accesses.
36 */
37
John Johansen680cd622017-01-16 00:42:27 -080038#define DEBUG_ON (aa_g_debug)
39#define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
John Johansen12557dc2017-01-16 00:42:13 -080040#define AA_DEBUG(fmt, args...) \
41 do { \
John Johansen680cd622017-01-16 00:42:27 -080042 if (DEBUG_ON) \
John Johansen12557dc2017-01-16 00:42:13 -080043 pr_debug_ratelimited("AppArmor: " fmt, ##args); \
44 } while (0)
45
John Johansen680cd622017-01-16 00:42:27 -080046#define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
47
48#define AA_BUG(X, args...) AA_BUG_FMT((X), "" args)
49#ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
50#define AA_BUG_FMT(X, fmt, args...) \
51 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
52#else
53#define AA_BUG_FMT(X, fmt, args...)
54#endif
55
John Johansen12557dc2017-01-16 00:42:13 -080056#define AA_ERROR(fmt, args...) \
57 pr_err_ratelimited("AppArmor: " fmt, ##args)
58
59/* Flag indicating whether initialization completed */
John Johansen545de8f2017-04-06 06:55:23 -070060extern int apparmor_initialized;
John Johansen12557dc2017-01-16 00:42:13 -080061
62/* fn's in lib */
John Johansenb91deb92017-05-22 02:47:22 -070063const char *skipn_spaces(const char *str, size_t n);
John Johansen12557dc2017-01-16 00:42:13 -080064char *aa_split_fqname(char *args, char **ns_name);
John Johansen3b0aaf52017-01-16 00:42:23 -080065const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
66 size_t *ns_len);
John Johansen12557dc2017-01-16 00:42:13 -080067void aa_info_message(const char *str);
John Johansen12557dc2017-01-16 00:42:13 -080068
John Johansen12557dc2017-01-16 00:42:13 -080069/**
70 * aa_strneq - compare null terminated @str to a non null terminated substring
71 * @str: a null terminated string
72 * @sub: a substring, not necessarily null terminated
73 * @len: length of @sub to compare
74 *
75 * The @str string must be full consumed for this to be considered a match
76 */
77static inline bool aa_strneq(const char *str, const char *sub, int len)
78{
79 return !strncmp(str, sub, len) && !str[len];
80}
81
82/**
83 * aa_dfa_null_transition - step to next state after null character
84 * @dfa: the dfa to match against
85 * @start: the state of the dfa to start matching in
86 *
87 * aa_dfa_null_transition transitions to the next state after a null
88 * character which is not used in standard matching and is only
89 * used to separate pairs.
90 */
91static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
92 unsigned int start)
93{
94 /* the null transition only needs the string's null terminator byte */
95 return aa_dfa_next(dfa, start, 0);
96}
97
John Johansenefeee832017-01-16 00:42:28 -080098static inline bool path_mediated_fs(struct dentry *dentry)
John Johansen12557dc2017-01-16 00:42:13 -080099{
100 return !(dentry->d_sb->s_flags & MS_NOUSER);
101}
102
John Johansena1bd6272017-06-09 07:09:05 -0700103
104struct counted_str {
105 struct kref count;
106 char name[];
107};
108
109#define str_to_counted(str) \
110 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
111
112#define __counted /* atm just a notation */
113
114void aa_str_kref(struct kref *kref);
115char *aa_str_alloc(int size, gfp_t gfp);
116
117
118static inline __counted char *aa_get_str(__counted char *str)
119{
120 if (str)
121 kref_get(&(str_to_counted(str)->count));
122
123 return str;
124}
125
126static inline void aa_put_str(__counted char *str)
127{
128 if (str)
129 kref_put(&str_to_counted(str)->count, aa_str_kref);
130}
131
132
John Johansenfe6bb312017-01-16 00:42:14 -0800133/* struct aa_policy - common part of both namespaces and profiles
134 * @name: name of the object
135 * @hname - The hierarchical name
136 * @list: list policy object is on
137 * @profiles: head of the profiles list contained in the object
138 */
139struct aa_policy {
John Johansenbbe4a7c2017-01-16 00:42:30 -0800140 const char *name;
John Johansena1bd6272017-06-09 07:09:05 -0700141 __counted char *hname;
John Johansenfe6bb312017-01-16 00:42:14 -0800142 struct list_head list;
143 struct list_head profiles;
144};
145
146/**
John Johansen6e474e32017-01-16 00:42:29 -0800147 * basename - find the last component of an hname
John Johansenfe6bb312017-01-16 00:42:14 -0800148 * @name: hname to find the base profile name component of (NOT NULL)
149 *
150 * Returns: the tail (base profile name) name component of an hname
151 */
John Johansen6e474e32017-01-16 00:42:29 -0800152static inline const char *basename(const char *hname)
John Johansenfe6bb312017-01-16 00:42:14 -0800153{
154 char *split;
155
156 hname = strim((char *)hname);
157 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
158 hname = split + 2;
159
160 return hname;
161}
162
163/**
164 * __policy_find - find a policy by @name on a policy list
165 * @head: list to search (NOT NULL)
166 * @name: name to search for (NOT NULL)
167 *
168 * Requires: rcu_read_lock be held
169 *
170 * Returns: unrefcounted policy that match @name or NULL if not found
171 */
172static inline struct aa_policy *__policy_find(struct list_head *head,
173 const char *name)
174{
175 struct aa_policy *policy;
176
177 list_for_each_entry_rcu(policy, head, list) {
178 if (!strcmp(policy->name, name))
179 return policy;
180 }
181 return NULL;
182}
183
184/**
185 * __policy_strn_find - find a policy that's name matches @len chars of @str
186 * @head: list to search (NOT NULL)
187 * @str: string to search for (NOT NULL)
188 * @len: length of match required
189 *
190 * Requires: rcu_read_lock be held
191 *
192 * Returns: unrefcounted policy that match @str or NULL if not found
193 *
194 * if @len == strlen(@strlen) then this is equiv to __policy_find
195 * other wise it allows searching for policy by a partial match of name
196 */
197static inline struct aa_policy *__policy_strn_find(struct list_head *head,
198 const char *str, int len)
199{
200 struct aa_policy *policy;
201
202 list_for_each_entry_rcu(policy, head, list) {
203 if (aa_strneq(policy->name, str, len))
204 return policy;
205 }
206
207 return NULL;
208}
209
210bool aa_policy_init(struct aa_policy *policy, const char *prefix,
John Johansend102d892017-01-16 00:42:31 -0800211 const char *name, gfp_t gfp);
John Johansenfe6bb312017-01-16 00:42:14 -0800212void aa_policy_destroy(struct aa_policy *policy);
213
John Johansen12557dc2017-01-16 00:42:13 -0800214#endif /* AA_LIB_H */